PITTSWORTH farmer Lachlan Stirling says what goes on farm, stays on farm when it comes to the application of agricultural chemicals.

Mr Stirling, who operates the 530 hectare grain property Gunbower in the Kincora district, said the selection of the most appropriate spray nozzles was critical to achieving that objective.

His comments follow the upcoming introduction of new rules meaning the popular broadleaf knockdown herbicide 2,4-D must now be applied through a coarse rated nozzle.

The rule change is designed to stop spray drift, which may result if the chemical is applied through fine nozzles. Fine nozzles produce a far smaller droplet that can be more easily dispersed in the atmosphere.

Government regulator, the Australian Pesticides and Veterinary Medicines Authority, says the changes will come into play at the start of October.

Cotton is particularly susceptible to 2,4-D. The chemical leaves most grasses including cereals largely unaffected.

What goes on farm, should stay on farm when it comes to chemicals. - Pittsworth grain grower Lachlan Stirling

“We only use 2,4-D on fallow country to control broadleaf weeds,” Mr Stirling said. “We’ve already been using coarse, spray guard nozzles so I see the new rules as a good thing. What goes on farm, should stay on farm when it comes to chemicals.”

A variety of broadacre crops are grown on Gunbower including sorghum, wheat, and chickpeas as well as cotton.

“We choose the nozzle that best suits the crop and chemical,” Mr Stirling said.

“Fine nozzles are usually required when weeds are particularly small because we’re trying to wet every weed.

“The large drops produced by a coarse nozzle are also distributed in the wider pattern. The bigger the drop the more risk there is a small weed will be missed. It’s not an issue in fallow country because we’re targeting bigger weeds.”